For self-comparison warning, check the source location of both the LHS and RHS to...

are expanded from macros (and if so, omit the warning).  Previously we were just looking at the
location of the binary expression.

Fixes <rdar://problem/8435950>.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@114044 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index a99d118d2bc585e67a98aeeb4c67369a82ba8110..20315084703932f2894a1e0a4d93db29eca0edeb 100644 (file)
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -5437,7 +5437,9 @@ QualType Sema::CheckCompareOperands(Expr *&lex, Expr *&rex, SourceLocation Loc,
   QualType rType = rex->getType();
 
   if (!lType->hasFloatingRepresentation() &&
-      !(lType->isBlockPointerType() && isRelational)) {
+      !(lType->isBlockPointerType() && isRelational) &&
+      !lex->getLocStart().isMacroID() &&
+      !rex->getLocStart().isMacroID()) {
     // For non-floating point types, check for self-comparisons of the form
     // x == x, x != x, x < x, etc.  These always evaluate to a constant, and
     // often indicate logic errors in the program.
@@ -5452,7 +5454,7 @@ QualType Sema::CheckCompareOperands(Expr *&lex, Expr *&rex, SourceLocation Loc,
     Expr *RHSStripped = rex->IgnoreParens();
     if (DeclRefExpr* DRL = dyn_cast<DeclRefExpr>(LHSStripped)) {
       if (DeclRefExpr* DRR = dyn_cast<DeclRefExpr>(RHSStripped)) {
-        if (DRL->getDecl() == DRR->getDecl() && !Loc.isMacroID() &&
+        if (DRL->getDecl() == DRR->getDecl() &&
             !IsWithinTemplateSpecialization(DRL->getDecl())) {
           DiagRuntimeBehavior(Loc, PDiag(diag::warn_comparison_always)
                               << 0 // self-

diff --git a/test/Sema/self-comparison.c b/test/Sema/self-comparison.c
index c5c0611e7c94dc27d3744be06d26136e945ec618..edb3a6a4c8a5fa169155f3ad6601e8621dabb287 100644 (file)
--- a/test/Sema/self-comparison.c
+++ b/test/Sema/self-comparison.c
@@ -75,3 +75,14 @@ int array_comparisons() {
 
 }
 
+// Don't issue a warning when either the left or right side of the comparison
+// results from a macro expansion.  <rdar://problem/8435950>
+#define R8435950_A i 
+#define R8435950_B i 
+
+int R8435950(int i) {
+  if (R8435950_A == R8435950_B) // no-warning
+   return 0;
+  return 1;
+}
+